1. Field of the Invention
The present invention relates to an electronic camera, such as a digital still camera, and more particularly to an electronic camera having a charge coupled device (CCD), which is capable of taking a picture with flash such that the exposure is correctly adjusted over the entire image area.
2. Description of the Prior Art
Recently, electronic cameras, such as digital still cameras, have been used both in place of conventional film cameras, and also for entering image data into a personal computer or other electronic device. Since the electronic camera has a CCD, which can vary its sensitivity and adjust to a higher sensitivity corresponding to the darkness of an object in the image, can take pictures at higher shutter speeds without flash even in low light situations. That is, since the CCD output signals are amplified by an amplifier with gain which is variable corresponding to ambient brightness, the camera does not have to employ the low shutter speeds, or use a flash unit, to the degree required with conventional cameras. However, when the gain of the amplifier is set too high, picture quality is degraded because noise in the CCD output signals is amplified with the same high gain. Therefore, even the electronic camera would be better to take a picture with flash so darker situation than that in which the quality of the picture cannot keep reasonably high without the flash.
For flash exposures, electronic cameras have the same problem as conventional film cameras: the flash exposure is determined by the combination of the flash power and the aperture of an iris diaphragm, adjusted for the distance from the flash unit to the object to be photographed. Thus when the image includes a central object and a background distant from the central object, the flash exposure cannot be adjusted correctly for both the central object and the background. When the flash exposure is adjusted to the central object, the background becomes unduly dark. Conversely, when the flash exposure is adjusted to the background, the central object becomes unduly bright.
Accordingly, the present invention provides an electronic camera capable of taking a flash picture in which the exposure is more correctly adjusted for the entire area, i.e. both a central area and a background.
This is achieved by an electronic camera for recording an image, comprising: image sensing means for providing electric signals representative of such image; exposure control means for logically dividing such image into plural areas and determining an optimum exposure for each such area; exposure means for exposing the image sensing means to each such area for the exposure determined by the exposure control means; data means for producing image data based on the electrical signals output from the image sensing means for each such optimum exposure; and means for combining the image data so produced into an overall resultant image.
The present invention also provides an electronic camera for recording an image, comprising: image sensing means for capturing such image and converting it to electric signals; first and second exposure control means for determining a first and second exposures, respectively, for first and second areas of such image; first and second exposure means for exposing the areas respectively to the image sensing means in accordance with the first and second exposures; image data means for producing first and second image data based on the electrical signals output from the image sensing means in response to the first and second exposures; and combining means for combining the first image data and the second image data into an overall resultant image.